Black females have the highest prevalence of overweight and obesity than any other racial-gender group in the United States with 4 out of 5 adult black females being overweight or obese. Furthermore, adult black females tend to lose less weight than whites undergoing the same obesity intervention regardless of treatment modality. Reasons for racial differences in weight loss outcomes are not fully understood, but suggest opportunities to further optimize obesity treatment approaches to reduce disparities. Behavioral weight loss (BWL) interventions offer one approach that has demonstrated effectiveness in promoting modest weight loss among some participants with obesity, but black females tend to lose less weight than their white counterparts in the same BWL program. We hypothesize that the higher prevalence of chronic psychological stress, which has been linked to weight gain over time and poorer weight loss in BWL programs, reported by black females contributes to the disproportionate prevalence of obesity and suboptimal weight loss observed among this group. Thus, stress management offers a novel approach to weight management for black females. Our preliminary work suggests that incorporating a strong stress management component into an evidence- based BWL program can potentially lead to better outcomes than an evidence-based BWL program alone. For this proposal, we will test the effectiveness of a 12-month culturally-targeted, stress management-enhanced BWL intervention on weight loss and stress reduction in a fully powered randomized, controlled trial (n=340). Adult black females with obesity will be randomized to either a stress-management enhanced BWL intervention (BWL-Stress) or the same BWL intervention alone (BWL-alone). The specific aims are to 1) conduct a randomized, controlled trial to determine the effects on body weight of BWL-Stress compared to BWL-Alone among adult black females with obesity and elevated stress, 2) evaluate intervention effects on psychological stress as measured by a validated survey instrument and a stress biomarker, and 3) using a multiple mediation model, test whether the relationship between the intervention and weight change is mediated by perceived stress, energy intake, and physical activity. The primary outcome is weight change at month 6. Secondary outcomes will include changes in stress measures (e.g., survey measures, cortisol), blood glucose, energy intake, and physical activity at month 6. We will also assess process measures (e.g, treatment adherence, treatment burden). We will also evaluate each outcome at month 12. This novel approach for enhancing an evidence-based BWL program with culturally-targeted stress management strategies for black females targets an understudied contributor to weight management among a population at high risk for obesity and obesity-related chronic diseases (e.g. type 2 diabetes, cancer). This study will also elucidate behavioral mechanisms linking our novel intervention to study outcomes. If proven effective, it would have significant clinical and public health implications for weight management among black females.